Which smart thermostat works with a mini split?

Two answers circulate, and the brand decides between them#

The first answer says a mini split cannot take a normal smart thermostat, so buy an infrared controller. That is how smart thermostats and the C wire treats it, and for most heads it is the cheapest route, but it is not universal. Mitsubishi's PAC-US444CN-1 data sheet says the interface "Allows a HVAC Thermostat or I/O Controller to control" its CITY MULTI, M-Series and P-Series indoor units, and lists Nest and Honeywell among the thermostats tested. Fujitsu's UTY-TTRXZ1 does the same for third-party thermostats "with 24Vac outputs, such as Honeywell, Nest."

The second answer says any smart thermostat works with a mini split once you add an adapter. That is wrong for Daikin. Its ductless wall route is the DAPT-ONE-VMS, which the data sheet calls the "Daikin ONE Translation Adaptor", and every compatibility table it appears in is for the Daikin ONE+ thermostat. Nothing in Daikin's documents read here lets a Nest or ecobee drive a Daikin head.

So infrared works for any brand if the remote qualifies, and a wall thermostat works for some brands if you buy the maker's interface. Two things you can check in a minute decide which: the remote in your hand and the model label on the indoor unit.

The three routes, side by side#

Prices as listed in October 2026. One device per indoor head unless the row says otherwise.

Infrared is the only brand-blind route, and the remote is its gate; every other row is tied to one maker's connector. The wired interfaces also trade features for a familiar wall thermostat: Mitsubishi's PAC-US444CN-1 lists "Cool, Heat, Fan, and Off", with no dry mode, which Mysa's infrared route does offer.

Route 1: an infrared controller, if your remote qualifies#

An infrared controller is a small wall box that learns the remote and sends the same commands. Mysa says it "plugs into a standard outlet and sends infrared commands, just like the original handheld remote", on "micro USB power." That is why it is the default suggestion in a smart home for renters: nothing in the head or the wall changes.

The full-state remote rule#

Mysa's compatibility check comes down to the remote's screen. You are likely compatible if "The remote has a display that shows the complete state: target temperature, operating mode, and fan speed." You are likely not if:

• The remote has no screen. "A remote with no display usually sends incremental commands. Mysa needs a full-state command containing the complete temperature, mode, and fan setting."
• The screen shows only temperature. "The remote should also show the operating mode and fan speed."
• The remote is radio or Bluetooth. "Radio-frequency and Bluetooth remotes are not compatible with Mysa's IR control."
• There is only a wired wall controller, which leaves no infrared commands to imitate.
• Something blocks the line of sight between the controller and the head's receiver: "walls, furniture, curtains, or another obstruction."

The reason applies to any infrared controller. A button-only remote sends "one degree warmer" or "next mode", so the result depends on what the head was already doing, and a controller that cannot read the head back cannot land it on 70°F in Heat. A full-state remote sends the whole setting with every press.

Sensibo states its rule more broadly, "Your AC must have a working infrared remote control", and checks by remote model. Its pages say nothing about remote screens, so find your exact remote on its list rather than assume a button-only one is covered.

What you give up#

Infrared is one-way, and Mysa lists what it does not reproduce: "Freeze protection, low-temperature heat-pump modes, Follow Me/I-Feel remote sensing, Turbo/Powerful/Jet, Eco, timers, and changing the head-unit display." Keep the original remote for those. Three more limits:

• One controller per head. Mysa: "Plan on one Mysa for each indoor head or room." Sensibo: "each unit requires its own Sensibo device." Four heads means $556 in Mysas at list.
• 2.4 GHz Wi-Fi only, with Bluetooth for setup, the band 2.4 GHz pairing problems are about. Mysa says manual controls stay available without Wi-Fi.
• No Matter listed. Mysa's mini-split page names Alexa, Google Assistant and Apple HomeKit. Matter's thermostat type, described in Matter device types, reaches an infrared head only through a hub acting as a Matter bridge.

If you already run a hub with an infrared blaster, Homey Pro can present an infrared air conditioner to voice assistants as a thermostat, and the hub comparison lists which other hubs carry infrared. The remote rule still applies: a learned button-only remote gives you button presses, not set points.

Route 2: the maker's Wi-Fi adapter#

Mitsubishi and Fujitsu sell modules that plug into the indoor unit and put it on your network. Because they talk to the board rather than imitating the remote, the remote's screen and the line of sight stop mattering.

• Mitsubishi. The Comfort app page says some systems have Wi-Fi built in, and for the rest "A Wireless Interface Adapter can be ordered as an accessory for field installation." The PAC-USWHS002-WF-2 uses CN105, one per indoor unit, at $229 from GotDuctless.
• Fujitsu. The UTY-TFSXH4 controls "compatible AIRSTAGE H-Series wall mount units" and runs from the indoor unit's 12 V output, at $178.45. Fujitsu says its newer AIRSTAGE Mobile adapter fits the indoor units that took the older FGLair adapters.
• Daikin. No Daikin Wi-Fi adapter document could be read, so the page makes no claim about which models take which module.

An adapter puts no thermostat on the wall. Mitsubishi's answer is the MHK2, a wireless wall control using "Redlink 3.0 to communicate to a receiver module" on CN105, per Mitsubishi's Application Note 3052 as reproduced by Munch's Supply. The receiver and the Wi-Fi adapter can share the port, on "the extra CN105 plug on the Wireless Interface 2", but only once the adapter is commissioned in the app, and a change can take "as long as five minutes" to show on the other side.

Route 3: a wired interface for a 24 V wall thermostat#

This is the route for someone who already owns a Nest, ecobee or Honeywell, or wants the same thermostat in every room. The interface sits at the indoor unit and translates the thermostat's calls into the maker's own signals.

Mitsubishi PAC-US444CN-1 and PAC-US445CN-1#

The PAC-US445CN-1 is the version GotDuctless lists today, at $196.56. It covers the same three lines plus PAA intelli-HEAT cased coils, and names Nest, Honeywell Lyric and ecobee as compatible thermostats.

Not every M-Series head qualifies, and the suffix on the model label matters. From the PAC-US444CN-1 compatibility chart:

The chart dates from 2017, so heads launched since are not on it. For a newer model, check Mitsubishi's current chart before buying.

Fujitsu UTY-TTRXZ1#

GotDuctless describes the UTY-TTRXZ1 as letting Fujitsu indoor units "be connected to third party thermostats with 24Vac outputs", with a 24 Vac transformer in the kit. ACHR News, on Fujitsu's 2018 launch for Halcyon mini-split and Airstage VRF systems, lists "on/off control, operation mode, room temperature, fan speed, and error notifications via LED lights."

Its defining number is 16: "Up to 16 indoor units may be controlled with a single thermostat controller," and they "operate using identical settings." That suits several heads in one open space, and it is the wrong tool for bedrooms that each want their own set point.

Daikin: the ONE+ or nothing on the wall#

Daikin's DAPT-ONE-VMS sheet lists the ductless families the ONE+ thermostat runs through the adaptor: R-32 S21 (FTXC, FTXM4), R-410A S21 (CDXS, CTXS2, FDXS, FTX2, FTXB2, FTXF2, FTXG, FTX09_12N2, FTX15_18_24N3, FTRX, FTXS, FVXS3), and P1/P2 (FDMA, CDMQ, FDMQ, FFQ). The R-32 CMXV units are listed without the adaptor footnote. The adaptor takes "110-230 VAC 60Hz", connects to "1 for S21 indoor units / 16 for P1P2 indoor units", and allows 125 ft of thermostat wire. Some S21 heads also need a Daikin S21 adapter (KRP067A41E, KRP980B2E or KER087A41), per the sheet's footnotes.

With a Daikin head and a wish for a Nest or ecobee, the documents read here give no route. Use the ONE+ or go infrared.

Which route, by situation#

Photograph each head's model label and the remote's screen, and add both to the pre-purchase checklist. The suffix (NA, NA-8, NA4) decides the Mitsubishi rows, and the wired routes need a 24 V supply fitted by an installer.

What changes once the head is smart#

• Two controllers at once. With infrared, anyone using the original remote changes the head without the controller knowing, because it only knows what it sent. Mitsubishi documents the opposite for its board-connected parts: a command from the app appears on the MHK2's display, and one from the MHK2 appears in the app.
• Outages. Mitsubishi lists "Auto recovery after power failure" for the PAC-US444CN-1. None of the documents read say how each route behaves without internet, beyond Mysa's manual controls; the questions to ask are in what still works in an internet outage and local versus cloud control.

Where this page stops#

• Read here, as of October 2026: Mysa's and Sensibo's own compatibility pages, Mitsubishi's PAC-US444CN-1 data sheet and Comfort app page, Daikin's DAPT-ONE-VMS sheet and ONE+ flyer, a Fujitsu FAQ, and distributor listings and a trade report for the Mitsubishi and Fujitsu parts. Mysa's main compatibility article returned an error, so its quick check and incompatible-systems pages were used.
• Not read: LG, Samsung, Gree, Midea and MRCOOL documents (MRCOOL's support site refused the request), Daikin's Wi-Fi adapters, and ecobee's or Google's own mini-split statements. The page makes no claim about them.
• Prices are single listings on the day read, before tax and installation.
• Other equipment. A furnace or air handler on a 24 V thermostat is covered in smart thermostats without a C wire, window and portable units in window air conditioners on a smart plug, and electric baseboard in smart thermostats for baseboard heaters.